1. Field
One embodiment of the invention relates to an electronic apparatus having a heating element, such as a CPU, and more particularly, to a structure for cooling a heating element through use of a fan.
2. Description of the Related Art
A CPU is incorporated in an electronic apparatus, such as a portable computer. The heat generated when the CPU is in operation increases in association with an increase in processing speed and addition of functions. When the temperature of the CPU has increased excessively, a loss of efficient operation of a CPU arises or the CPU becomes inoperative.
In order to enhance heat dissipation performance of the CPU, a related-art electronic apparatus is provided with an air-cooled cooling device for forcefully cooling the CPU. The cooling device has a heat sink thermally connected to a CPU, and a fan for sending cool air to the heat sink.
The heat sink and the fan are integrated into a single module and housed in a casing of the electronic apparatus. The heat sink assumes the shape of a flat box having a heat-receiving surface for receiving heat from a CPU, a radiating fin, and a cool air passage. The heat sink is formed from, e.g., a metallic material having superior thermal conductivity, such as an aluminum alloy. The radiating fin is exposed to the cool air passage. The cool air passage is separated from the inside of the casing, and the downstream end of the cool air passage is formed into a vent port which is opened in a sidewall or rear wall of the casing.
The fan has a fan case and an impeller. The fan case has a take-in port and an outlet port. The impeller is housed in the fan case. The impeller takes air in by way of the take-in port, and sends the thus-taken air to the cool air passage from the outlet port. Thus, the air sent from the fan flows through the cool air passage as cool air, and cools the heat sink, which receives heat from the CPU, during the course of flow. The cool air heated through the heat exchange performed by the heat sink is emitted from the downstream end of the cool air passage to the outside of the casing by way of the vent port.
Moreover, in a related-art cooling device, an air guide passage is formed between the upper surface of the fan case and the casing. The air guide passage is for connecting an air intake port of the casing to the take-in port of the fan case. The air guide passage is separated from the inside of the casing by means of a partition member such as a sponge. The partition member is interposed between the fan case and the casing (see, e.g., JP-A-2002-368467).